Heat exchange device



Aug. 15, 1933. J. EPSTEIN HEAT EXCHANGE DEVICE Filed May 14, 1930 4Sheets-Sheet l INVENTOR. JOSHUA E PS TE/N A TTORNEY.

15, 1933- J. EPSTEIN HEAT EXCHANGE DEVICE Filed May 14, 1930 4Sheets-Sheet 2 INVENTORv JOSHUA E PS TE /N A TTORNE Y.

Aug. 15, 1933. E E 1,922,844

HEAT EXCHANGE DEVICE Filed May 14, 1950 4 Sheets-Sheet 3 FIG. 4

yea/Flea INVENTOR. JOSHUA EPSTE/N ATTORNEY.

Aug. 15, 1933. J, EPSTEIN 1,922,844

HEAT EXCHANGE DEVI CE Filed May 14, 1930 4 Sheets-Sheet 4 INVENTOR.JOSHUA EPSTE/N War,

A TTORNE Y Patented Aug. 15, 1933 hurrah STATES PATENT OFFICE] 2 Claims.

This invention relates to heat exchange apparatus and has for its objectthe production of an improved apparatus of this class.

This invention relates further to evaporators and has for its object theproduction of a new and improved evaporator.

Evaporators now in general use have either a plurality of an inclinedcoils or a plurality of noninclined coils. Any plane which is at rightangles to the axis of the imaginary .cylinder around which the coils arewound will cut the axis of each of the said coils in a certain point.However, the temperature of the heating element in the said coils willbe different at each of the points so cut. This results in many seriousdisadvantages among which are unequal evaporation, unbalanced convectioncurrents, improper circulation and uneven velocity in the substancebeing evaporated. It is an object of this invention to produce anevaporator having a plurality of coils and so constructed that equaltemperature conditions will exist at all points out by the coils in anyplane at right angles to the axis of the imaginary cylinder around whichthe coils are wound and that all such points will be equally spacedaround the circumference of the said imaginary cylinder, thuseliminating the above enumerated as well as other objections due tounequal temperature conditions at equivalent points in the same plane.This is effected by the use of multiple thread coils, that is aplurality of equal slanting coils having a common imaginary cylinder attheir base, having all of the inlets in a common plane and equallyspaced around a given periphery and further having all of their outletsin a common plane and also equally spaced around a given periphery.

Another object of this invention is to produce an evaporator wherein themaximum heating, efiiciency will be secured for the space occupied.

Another object of this invention is to produce an evaporator having animproved condenser element whereby the efficiency of the entire devicewill be increased.

Another object of this invention is to produce an evaporator with coilsor fluid chambers having an appreciably greater pitch than that now inuse without in any way lowering the efiiciency of the unit.

These as well as other objects and advantages which result from my novelconstruction will become more apparent from the'following descriptionand the drawings which form a part thereof. I

In the drawings Figure l is a front View showing the invention embodiedin a milk evaporator. Parts of the shell are broken away to better showthe novel features and portions of these are shown in perspective. Inthis particular embodiment each unit is composed of two coils and each'coil in the unit is made up of an outer and inner coil member.

Figure 2 is a section taken along the line 2--2 of Figure 1.

Figure 3 is an enlarged front view with the shell broken away andshowing a coil unit.

Figure 4 is a section taken along the line 44 of Figure 3.

Figure 5 is a section taken along the line 5-5 of Figure 4.

Figure 6 is a section taken similarly to Figure 2 of unit having threeindependent coils.

Figure '7 is a front view of the disclosure shown in Figure 6.

Referring more particularly to the drawings wherein similar referencenumerals denote simipartsreference numeral 1 denotes the evaporator as aunit composed of a heating section 2 and a condenser section 3,contained in a shell having a bottom portion 10, a cylindrical bodyportion. 11 and a top portion 12. The evaporator is provided with amanhole l3 and the usual gage (not shown), neither of which constitutesa part of this invention and for that reason will not be here furtherdiscussed.

The heating section 2 is composed of the usual portion or pan 4 adaptedto hold the milk to be treated and a plurality of equal, cooperating,equally slanting and oppositely disposed pairs of coils 5--5'. It is tobe noted that the two coils form a multiple thread. The coils whichappear on the same half section of the imaginary cyli'n der around whichthey are wound slant in the same direction. Those which. appear onopposite faces only slant in opposite directions.

Each of the coils 5 is composed of an outer coil 6 and a substantiallyparallel inner coil 7 having a common inlet 8 and common outlet 9, whileeach of the coils 5" is composed of an outer coil 6' and a substantiallyparallel inner coil 7' having a common inlet 8' and a common outlet 9'.The inlets 8 and 8 and the outlets 9 and 9 are connected to steammanifolds in the manner well known in the art and for that reason willnot be further described here. The inlets 8 and 8 are in the same plane,are oppositely disposed and are substantially at the same distance fromthe source of steam supply. The outlets 9 and 9 are in the same planeand oppositely disposed. (Since there are only two coils in the unit andsince they are equally spaced around the periphery of a given circle theinlets or the outlets must be 180 degrees apart or oppositely disposed.)Because of this particular structure, the cooperating, equal, equallyslanting, and oppositely disposed pairs of coils have the followingcharacteristics:

(a) Two coils fit together to form a cooperating pair, see particularlyFigures 1 and 3, thus resulting in the maximum heating efficiency forthe space occupied.

' (b) The coils have equal gradients so that th following results areobtained:

(1) The grade in the coils permits the steam which condenses in thecoils to drain away. Thus there is always exposed to th milk which isbeing evaporated coils which are always full of steam and which are thesame temperature at all points of any given cross sectional area of thecoil, thus causing an even and rapid circulation of the milk around thecoils. Caking of the milk on the coils is thus prevented.

(2) The coils being full of steam the entire coil surface at any pointtakes part in the heat exchange at the heat exchange value of steam, nowet areas being present to change the heat exchange value at any pointof the coil on a given circumference with respect to the other points.

The particular structure of the coils further results in the fact thatall points which the coils cut on any horizontal plane (that is theplane at right angles to the axis of the imaginary cylinder around whichthe coils are wound) are equidistant from the inlets of the said coilsand are equally spaced around the periphery of the circumference of thesaid cylinder, thus assuring equal temperatures for all equivalentpoints in the same plane, since two such points of any two cooperatingcoils are at the same distance from the entrance into the coil of steamcoming from a common source and therefore have the same potential heatexchange capacity.

This feature can be seen by inspecting any figure of the drawings andhas been particularly illustrated in Figures 2, 3, 4 and 5.

An inspection of Figures 1, 3 and discloses that any horizontal planewill out only a pair of cooperating coils and at diametrically oppositepoints both the inner and outer coils will be out.

An examination of Figures 2 and 4 discloses any two diametricallyopposite points P and P on the outside coil members 6 and 6' of acooperating pair of coils 5 and 5 have equivalent a: and y coordinates.That is the points may lie in different quadrants causing thecoordinates to have different algebraic signs but they are numericallyequal. The same holds true for any two diametrically disposed points P1and Pl on the inner coils '7 and. 7 respectively.

An examination of Figures 3 and 5 discloses that the same is true forpoints having ar-s or 'ye coordinates.

In Figure 3 compare points P3 with P-3 on the outer coils 6 and 6': Alsopoints P-4 with P-4 on the inner coils '7 and '7 respectively.

In Figure 5 compare points P 5 with P-5, P7 with P-7, P-9 with P9', all.on the other coils 5 and 5 respectively. Also compare points of takingthe true yy axis for Figure 5 it has been shifted somewhat and amodified y axis used. This has been done for the double purpose ofpicking a point off the conventional right angular axes and also for thepurpose of more clearly illustrating the relative positions of theentrance and exit points of a cooperating pair of tubes 5 and 5'.)

(d) As a direct result of the fact that the temperature conditions atany two diametrically disposed points on any cooperating pair of coilsare equal, the following advantages are obtained:

(1) Balanced and symmetrical convection currents.

(2) Even circulation of the contents being evaporated.

(3) Even velocity in the contents being evaporated.

l) Equal rate of evaporation of all points in the evaporator havingequivalent '1 a coordinates.

From the above it is seen that the novel structure here disclosed givesall of the benefits which are obtained from a constant, steady heat.

Thecondenser portion 3 is composed of cooling element inlet means 14, abaffie 15, a plate 16 having a plurality of perforations 17 therein, aplate 18 formed 'in an inverted frustrum of a cone and having its loweredge 19 terminating below the top edge 21 of the funnel or outlet 20. Aplurality of the usual cleaning plugs or manhole 22 are provided in amanner well known in the art.

Although the operation of the device is b lieved to be obvious from theabove disclosure yet to obviate any possibility of misunderstanding thefollowing detailed description is here given.

The milk which is to be evaporated is introduced into the evaporator inthe usual manner well known in the art in the amount desired. Steam isintroduced into the coils in the usual manner. As the liquid evaporatesit proceeds upward in a vapor through the mouth 22, striking the bottomplate 23 of the baffie l5 and is deflected towards the space 24 andwhere it is condensed and drawn out through the opening 25 by a vacuumpump, not shown, in the manner well known in the art.

The condensing fluid (water in this particular case) enters through thepipe 14, accumulates in the cup shaped portion 26 of the baffle andtrickles over the sides 27 of the baflie 15 onto the plate 16, throughthe perforations 17, from where itdrops into the opening 28, meeting thevapors which are being deflected and drawn into the space 2 1 by theplate 23 of the bafiie 15 and by the pump, not shown. It is to be notedthat the ends 29 of the deflector plate 23 extend beyond the edges 21 ofthe funnel and also beyond the edge 30 of the sides 27.

The condensing fluid takes up the heat of the vapors and helps tocondense them so that they may be drawn off through the outlet 25 by thepump, not shown. Because of the peculiar construction of the plate 18the vapors rising from the evaporator and the condensing liquid are bothconstricted into a smaller space in their passage from the space 28 tothe space 24. This results in a better intermingling of the condensingliquids with the vapors rising from the evaporator. thus making forbetter condensation.

' When the evaporation process has been carried to the point desired,the supply of steam .is cut off and the steps well known in the art arefollowed. The solid substance remaining in the kettle is withdrawn inthe manner well known i the same temperature.

in the art. These steps do not constitute a part of this invention, arewell known in the art, and for these reasons will not be described inanydetail here.

During the evaporation process steam continually enters through theinlets 8 and 8 of each coil and leaves by the outlets 9 and 9 of thesaid coils. It is to be noted that the steam for any pair of cooperatingcoils 5 and 5' comes from a common source and enters the coil atpractically Since the :c, y, z coordinates of any two diametricallyopposite points of cooperating coils are always equivalent, it isobvious that the steam in its course through the coils 5 and 5 meets thesame temperature conditions at all points having equivalent at, y, acoordinates and, therefore, the reaction c'ausedand the heat exchangedat these points by either coil will always be equal to that of theother.

t is to be distinctly understood that although the invention has beendescribed in detail by reference to a single pair of cooperating coils 5and 5, each of the said coils 5 and 5 being composed of an outer andinner coil respectivel it is not to be limited to such a structure. Anynumber of coils may be used whether odd or even. In Figures 6 and 7 amodification employing three or an odd number of coils is shown.

Referring more particularly to Figures 6 and 7 it is seen that theevaporator is provided with three equal coils A, B and C having inlets31, 32 and 33 respectively int-he same plan and equally spaced aroundthe periphery of a circle which could be circumscribed or inscribedaround the coils. In this particular illustration the inlets must bespaced 120 degrees apart since there are three inlets. The col. A, B andC are arranged at an equal gradient in multiple thread formation. It isto be noted that coils on the same half section of the imaginarycylinder around which they are wound slant in the same direc.

tion, while those around on the opposite side slant in the oppositedirection. The numerical value of the tangent or gradient is equalhowever for the coils on either half-section. The inlets 31, 32 and 33are connected to a common source of steam so that the steam entering anyone coil is of equal quality to that entering any of the other coils.

The coils A, B and C have common outlets as, 35 and 36 respectively inthe same plane and equally spaced around the periphery of a circle whichcould be circumscribed around or inscribed within the coils. In thisparticular case the outlets, since there are three, must be spaced onehundred and twenty (120) degrees apart.

It is to be noted that the coils are equal, equally slanting, haveinlets in a common plane and equally spaced around the periphery of acircle circumscribed about or inscribed Within the coils or around thecircumference of the cylinder around which the coils are wound, haveoutlets in a common plane and equally spaced around the periphery of acircle which may be circumscribed about or inscribed within the coils oraround the circumference of the cylinder around which the coils arewound and that this structure results in the fact that any horizontalplane (that is the plane at right angles to the axis of the imaginarycylinder around which the coils are wound) will cut points on each ofthe three coils that are equally distant from their respective inletsand equally spaced around the periphery of the circumference of the saidcylinder, thus resulting in equal temperatures for all equivalent pointsin in the coils being spaced 180 degrees apart as to inlets andoutlets.)

' It is to be noted that since the inlets 31, 32 and 33 are equallyspaced around the periphery of a circle angle a angle a angle [1:120degrees.

In any horizontal plane any point (P-13) chosen on any coil (coil A) ata vector distance r and angle 1 from a base line de ermined by thediameter passing through center of the inlet 31 of the said coil willhave equivalent points .P--l3' and P-lB" respectively on the remainingcoils B and C, at a vector distance r and at the angles on which isconstant at 120 degrees) plus 'r and 2 a plus 7' respectively, from thesaid base line. The coordinates on, r and 2 a, 1' fall on a passingthrough the center of the inlets 32 and 33.

The points having coordinates (a|-r)T and 2a+T)7 are, therefore, at anangle 'r distant from the inlet base lines of their respective coils.The points P-lB, P-l3 and P-l3" are therefore equally spaced around theperiphery of the circumference of the said imaginary cylinder.

Compare further points P-11, P-ll' and P-ll on coils A,B and Crespectively in Figure '7 which were cut by the horizontal plane QQ at adistance it from the horizontal plane passing through the center linesof the inlets 31, 32 and 33 respectively. These points are equallyspaced around the pe'ripheryof the said imaginary cylinder. measuredalong the coil A from the inlet 31 to P-ll is equalto that from theinlets 32 and 33 to points P-ll and P--ll respectively. Compare furtherpoints P-lZ, P 12 and P--l2 on coils A, B and C respectively cut by thehorizontal plane O() at a distance is from the horizontal plane passingthrough the center line of the inlets. As has been previously proved thepoints are equally spaced around the periphery of the imaginarycylinder. The distance I measured along the coil A from the points P-llto P-12 is equal to that from the points P--11' and P-ll" to Pl2' andP12'f respectively.

It is to be distinctly understood that the above disclosure is by theway of illustration only and It is seen that the distance L not by theway of limitation since many changes may be made in the constructionhere shown Without departing in any way from the spirit of my invention.

For instance, the number of pairs of coils may 135 be varied: Or insteadof using a plurality of pairs of double coils, an inner and outer coilfor each unit in a pair of coils, coils having only one coil in eachcoil unit may be used: Or, instead of using two or three coils in eachunit any other number may be used. It is understood from the abovedisclosure that if four coils are used the inlets are spaced or 90degrees apart, if five coils are used, the inlets are spaced or 72degrees, etc. The outlets of course are similarly spaced. All theinlets, however, are in one plane, all the outlets are in one planeand-the gradient is equal for all coils no matter how many are used: Orthe gradient and/or size of the coils may be varied: Or, instead ofevaporating milk, used in the specific embodiment herein disclosed, anyother substance of the same nature or requiring equivalent treatment maybe used: Or, instead of using steam as the heat exchange medium in thecoils, any medium may be used: Or, instead of using the coils hereindisclosed in the evaporator, it may be used in any heat exchange device,including refrigerators and refrigerating plants: Or the material andshape of any particular unit here disclosed may be varied.

It is, therefore, my desire that the claims which are hereto appendedand which define my invention should be limited only by the prior-art.

Itpis obvious from an examination of Figures 1 to 5 inclusive that thepitch of coils 5 and 5' is double that of the coils now in use. In thedisclosure herein the coil 5 is stretched so that the distance frominlet to outlet occupies the space occupied in previous art disclosuresby two coils one on top of the other. By placing coil 5' within coil 5in the manner herein disclosed the potential heat exchange value presentin the previously known art is not lost. In fact greater efliciency isobtained since the heat exchange medium passes through a greaterportionof the portion to be heated. From Figures 6 and 7 it is seen that wherethree coils are used in a unit the pitch is increased threefold.Likewise where four coils would be used the pitch is increased fourfold,etc.

Having described my new and useful is:-

1; An evaporator consisting of a shell, a pan member for holding asubstance to be treated, the said pan member terminating in a funneloutlet for the vapor, a chamber formed between the outer walls of thesaid funnel outlet of the said pan member and the said shell; one ormore units of plural, equal, cooperating and equal slanting coilsmounted in the said pan member for deliveringa heat exchange fluid tothe matter to be treated at an equal temperature for all points in thesame horizontal plane, the said coils in any one unit having theirinlets in the same plane, their outlets in thesame plane and inventionwhat I claim as their inlets and outlets equally spaced around thecircumference of the imaginary cylinder around which the coils arewound; and a condenser for condensing the fluids distilled from thesubstance being treated, the said condenser consisting of a baiilemember placed above the mouth of the said funnel having a concave bottomplate the edges of the said plate terminating beyond the edges of thesaid pan outlet, means for supplying a cooling fluid to the said bafilemember, a perforated plate mounted above the edges of the said concavebottom bafile member, the said concave member, the said perforated plateand the said funnel outlet combining to form a condensation chamber andmeans Within the said chamber and below the top of the said outlet forconstricting the area of the said condensation chamber; and a pumpoutlet formed in the said shell for permitting the condensed liquid tobe drawn off. 4

2. An evaporator consisting of a shell, a pan member for holding asubstance to be treated, the said pan member terminating in a funneloutlet for the vapor, a chamber formed between the outer walls of thesaid funnel outlet of the said pan member and the said shell; one ormore pairs of equal, cooperating and equal slanting coils mounted in thesaid pan member for delivering a heat exchange fluid to the matter to betreated at an equal temperature for all diametrically opposite points inthe same horizontal plane; and a condenser for condensing the fluidsdistilled from the substance being treated, the said condenserconsisting of a baflie member placed above the mouth of the said funnelhaving a concave bottom plate the edges of the said plate terminatingbeyond the edges of the said pan outlet, means for supplying a coolingfluid to the said bafile member, a perforated plate mounted above theedges of the said concave bottom bafiie member, the said concave member,the said perforated plate and the said funnel outlet combining to form acondensation chamber and means within the said chamber and below the topof the said outlet for constricting the area of the said condensationchamber, the said means consisting of a plate in the form of an invertedfrustrum of a cone; and a pump outlet formed in the said shell forpermitting the condensed liquid to be drawn off.

JOSHUA EPSTEIN.

